Contributors DYL contributed substantially to conception and design, performed the analysis and interpretation of data, drafted and revised
the article. JMM, ISL, and CSS contributed substantially to conception and design, and finally approved the revised version.
DC contributed substantially to conception and design, drafted and reviewed the article, and finally approved the revised
version.

Accepted 10 June 2012

Published Online First 4 July 2012

Abstract

Objective To investigate the factors associated with sexual debut among Korean adolescents.

Methods Based on a 2008 cross-sectional nationwide online survey conducted in 75 238 Korean middle and high school students aged
12–18 years (39 278 boys and 35 960 girls), demographic profiles of the reproductive health and factors associated with sexual
debut were analysed.

Results The proportion of adolescents who had heterosexual intercourse was 5.1%. The cumulative proportion of sexual debut at age
18 was 20%, and the median age was 17 years. Overall, 0.2% of girls reported past pregnancies, while 8.8% of sexually active
girls had ever been pregnant. A proportion of girls who underwent an induced abortion was 89.5%. Up to half (46.0% for boys
and 48.3% for girls) never resorted to contraception during coitus. After adjusting for covariates, attendance at general
and technical high school, low school record, drinking alcohol, smoking, drug use, high economic status and not living with
both parents were associated with the increased proportion of sexual debut in both genders. By contrast, internet use was
associated with a reduced risk of adolescent sexual debut.

Conclusion This study demonstrates the factors associated with sexual debut among Korean adolescents. This information may be helpful
for the prevention of unprotected sexual debut and subsequent teenage pregnancy in adolescents who are susceptible to initiating
sexual intercourse.

Footnotes

Competing interests None.

Patient consent Obtained.

Ethics approval This study was based on data from a national survey which was approved, under surveillance, by the Korea Centers for Disease
Control and Prevention (K-CDC) and Ministry of Health and Welfare of Korea, and this study only used publicly released data
from which all personal identifiers were removed by the K-CDC. In these contexts, approval was officially exempted by the
Ethics Committee at our institution (file number: 2011-12062).